Add type variations to Theme

4 files changed, 81 insertions, 24 deletions

diff --git a/doc/classes/@GlobalScope.xml b/doc/classes/@GlobalScope.xml
index 66511f5845..d0bd517050 100644
--- a/doc/classes/@GlobalScope.xml
+++ b/doc/classes/@GlobalScope.xml
@@ -2415,67 +2415,71 @@
 		<constant name="PROPERTY_HINT_ENUM" value="2" enum="PropertyHint">
 			Hints that an integer, float or string property is an enumerated value to pick in a list specified via a hint string such as [code]"Hello,Something,Else"[/code].
 		</constant>
-		<constant name="PROPERTY_HINT_EXP_EASING" value="3" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_ENUM_SUGGESTION" value="3" enum="PropertyHint">
+			Hints that a string property is can be an enumerated value to pick in a list specified via a hint string such as [code]"Hello,Something,Else"[/code].
+			Unlike [constant PROPERTY_HINT_ENUM] a property with this hint still accepts arbitrary values and can be empty. The list of values serves to suggest possible values.
+		</constant>
+		<constant name="PROPERTY_HINT_EXP_EASING" value="4" enum="PropertyHint">
 			Hints that a float property should be edited via an exponential easing function. The hint string can include [code]"attenuation"[/code] to flip the curve horizontally and/or [code]"inout"[/code] to also include in/out easing.
 		</constant>
-		<constant name="PROPERTY_HINT_LENGTH" value="4" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_LENGTH" value="5" enum="PropertyHint">
 			Deprecated hint, unused.
 		</constant>
-		<constant name="PROPERTY_HINT_KEY_ACCEL" value="5" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_KEY_ACCEL" value="6" enum="PropertyHint">
 			Deprecated hint, unused.
 		</constant>
-		<constant name="PROPERTY_HINT_FLAGS" value="6" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_FLAGS" value="7" enum="PropertyHint">
 			Hints that an integer property is a bitmask with named bit flags. For example, to allow toggling bits 0, 1, 2 and 4, the hint could be something like [code]"Bit0,Bit1,Bit2,,Bit4"[/code].
 		</constant>
-		<constant name="PROPERTY_HINT_LAYERS_2D_RENDER" value="7" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_LAYERS_2D_RENDER" value="8" enum="PropertyHint">
 			Hints that an integer property is a bitmask using the optionally named 2D render layers.
 		</constant>
-		<constant name="PROPERTY_HINT_LAYERS_2D_PHYSICS" value="8" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_LAYERS_2D_PHYSICS" value="9" enum="PropertyHint">
 			Hints that an integer property is a bitmask using the optionally named 2D physics layers.
 		</constant>
-		<constant name="PROPERTY_HINT_LAYERS_2D_NAVIGATION" value="9" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_LAYERS_2D_NAVIGATION" value="10" enum="PropertyHint">
 			Hints that an integer property is a bitmask using the optionally named 2D navigation layers.
 		</constant>
-		<constant name="PROPERTY_HINT_LAYERS_3D_RENDER" value="10" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_LAYERS_3D_RENDER" value="11" enum="PropertyHint">
 			Hints that an integer property is a bitmask using the optionally named 3D render layers.
 		</constant>
-		<constant name="PROPERTY_HINT_LAYERS_3D_PHYSICS" value="11" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_LAYERS_3D_PHYSICS" value="12" enum="PropertyHint">
 			Hints that an integer property is a bitmask using the optionally named 3D physics layers.
 		</constant>
-		<constant name="PROPERTY_HINT_LAYERS_3D_NAVIGATION" value="12" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_LAYERS_3D_NAVIGATION" value="13" enum="PropertyHint">
 			Hints that an integer property is a bitmask using the optionally named 2D navigation layers.
 		</constant>
-		<constant name="PROPERTY_HINT_FILE" value="13" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_FILE" value="14" enum="PropertyHint">
 			Hints that a string property is a path to a file. Editing it will show a file dialog for picking the path. The hint string can be a set of filters with wildcards like [code]"*.png,*.jpg"[/code].
 		</constant>
-		<constant name="PROPERTY_HINT_DIR" value="14" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_DIR" value="15" enum="PropertyHint">
 			Hints that a string property is a path to a directory. Editing it will show a file dialog for picking the path.
 		</constant>
-		<constant name="PROPERTY_HINT_GLOBAL_FILE" value="15" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_GLOBAL_FILE" value="16" enum="PropertyHint">
 			Hints that a string property is an absolute path to a file outside the project folder. Editing it will show a file dialog for picking the path. The hint string can be a set of filters with wildcards like [code]"*.png,*.jpg"[/code].
 		</constant>
-		<constant name="PROPERTY_HINT_GLOBAL_DIR" value="16" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_GLOBAL_DIR" value="17" enum="PropertyHint">
 			Hints that a string property is an absolute path to a directory outside the project folder. Editing it will show a file dialog for picking the path.
 		</constant>
-		<constant name="PROPERTY_HINT_RESOURCE_TYPE" value="17" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_RESOURCE_TYPE" value="18" enum="PropertyHint">
 			Hints that a property is an instance of a [Resource]-derived type, optionally specified via the hint string (e.g. [code]"Texture2D"[/code]). Editing it will show a popup menu of valid resource types to instantiate.
 		</constant>
-		<constant name="PROPERTY_HINT_MULTILINE_TEXT" value="18" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_MULTILINE_TEXT" value="19" enum="PropertyHint">
 			Hints that a string property is text with line breaks. Editing it will show a text input field where line breaks can be typed.
 		</constant>
-		<constant name="PROPERTY_HINT_PLACEHOLDER_TEXT" value="19" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_PLACEHOLDER_TEXT" value="20" enum="PropertyHint">
 			Hints that a string property should have a placeholder text visible on its input field, whenever the property is empty. The hint string is the placeholder text to use.
 		</constant>
-		<constant name="PROPERTY_HINT_COLOR_NO_ALPHA" value="20" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_COLOR_NO_ALPHA" value="21" enum="PropertyHint">
 			Hints that a color property should be edited without changing its alpha component, i.e. only R, G and B channels are edited.
 		</constant>
-		<constant name="PROPERTY_HINT_IMAGE_COMPRESS_LOSSY" value="21" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_IMAGE_COMPRESS_LOSSY" value="22" enum="PropertyHint">
 			Hints that an image is compressed using lossy compression.
 		</constant>
-		<constant name="PROPERTY_HINT_IMAGE_COMPRESS_LOSSLESS" value="22" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_IMAGE_COMPRESS_LOSSLESS" value="23" enum="PropertyHint">
 			Hints that an image is compressed using lossless compression.
 		</constant>
-		<constant name="PROPERTY_HINT_TYPE_STRING" value="24" enum="PropertyHint">
+		<constant name="PROPERTY_HINT_TYPE_STRING" value="25" enum="PropertyHint">
 			Hint that a property represents a particular type. If a property is [constant TYPE_STRING], allows to set a type from the create dialog. If you need to create an [Array] to contain elements of a specific type, the [code]hint_string[/code] must encode nested types using [code]":"[/code] and [code]"/"[/code] for specifying [Resource] types. For instance:
 			[codeblock]
 			hint_string = "%s:" % [TYPE_INT] # Array of inteters.
diff --git a/doc/classes/Control.xml b/doc/classes/Control.xml
index 47e26b7a2e..9c4600e4f3 100644
--- a/doc/classes/Control.xml
+++ b/doc/classes/Control.xml
@@ -1164,8 +1164,9 @@
 		<member name="theme" type="Theme" setter="set_theme" getter="get_theme">
 			The [Theme] resource this node and all its [Control] children use. If a child node has its own [Theme] resource set, theme items are merged with child's definitions having higher priority.
 		</member>
-		<member name="theme_custom_type" type="StringName" setter="set_theme_custom_type" getter="get_theme_custom_type" default="&amp;&quot;&quot;">
-			The type name used by this [Control] to look up its own theme items. By default, the class name of the node is used (e.g. [code]Button[/code] for the [Button] control), as well as the class names of all parent classes (in order of inheritance). Setting this property gives the highest priority to the type of the specified name, then falls back on the class names.
+		<member name="theme_type_variation" type="StringName" setter="set_theme_type_variation" getter="get_theme_type_variation" default="&amp;&quot;&quot;">
+			The name of a theme type variation used by this [Control] to look up its own theme items. When empty, the class name of the node is used (e.g. [code]Button[/code] for the [Button] control), as well as the class names of all parent classes (in order of inheritance).
+			When set, this property gives the highest priority to the type of the specified name. This type can in turn extend another type, forming a dependency chain. See [method Theme.set_type_variation]. If the theme item cannot be found using this type or its base types, lookup falls back on the class names.
 			[b]Note:[/b] To look up [Control]'s own items use various [code]get_theme_*[/code] methods without specifying [code]theme_type[/code].
 			[b]Note:[/b] Theme items are looked for in the tree order, from branch to root, where each [Control] node is checked for its [member theme] property. The earliest match against any type/class name is returned. The project-level Theme and the default Theme are checked last.
 		</member>
diff --git a/doc/classes/Theme.xml b/doc/classes/Theme.xml
index 7448697df3..969d8ab2a4 100644
--- a/doc/classes/Theme.xml
+++ b/doc/classes/Theme.xml
@@ -97,6 +97,15 @@
 				Clears the theme item of [code]data_type[/code] at [code]name[/code] if the theme has [code]theme_type[/code].
 			</description>
 		</method>
+		<method name="clear_type_variation">
+			<return type="void">
+			</return>
+			<argument index="0" name="theme_type" type="StringName">
+			</argument>
+			<description>
+				Unmarks [code]theme_type[/code] as being a variation of any other type.
+			</description>
+		</method>
 		<method name="copy_default_theme">
 			<return type="void">
 			</return>
@@ -319,6 +328,24 @@
 				Returns all the theme types as a [PackedStringArray] filled with unique type names, for use in other [code]get_*[/code] functions of this theme.
 			</description>
 		</method>
+		<method name="get_type_variation_base" qualifiers="const">
+			<return type="StringName">
+			</return>
+			<argument index="0" name="theme_type" type="StringName">
+			</argument>
+			<description>
+				Returns the base theme type if [code]theme_type[/code] is a valid variation type. Returns an empty string otherwise.
+			</description>
+		</method>
+		<method name="get_type_variation_list" qualifiers="const">
+			<return type="PackedStringArray">
+			</return>
+			<argument index="0" name="base_type" type="StringName">
+			</argument>
+			<description>
+				Returns a list of all variation for the given [code]base_type[/code].
+			</description>
+		</method>
 		<method name="has_color" qualifiers="const">
 			<return type="bool">
 			</return>
@@ -405,6 +432,17 @@
 				Returns [code]false[/code] if the theme does not have [code]theme_type[/code].
 			</description>
 		</method>
+		<method name="is_type_variation" qualifiers="const">
+			<return type="bool">
+			</return>
+			<argument index="0" name="theme_type" type="StringName">
+			</argument>
+			<argument index="1" name="base_type" type="StringName">
+			</argument>
+			<description>
+				Returns [code]true[/code] if [code]theme_type[/code] is marked as a variation of [code]base_type[/code] in this theme.
+			</description>
+		</method>
 		<method name="rename_color">
 			<return type="void">
 			</return>
@@ -599,6 +637,20 @@
 				Creates [code]theme_type[/code] if the theme does not have it.
 			</description>
 		</method>
+		<method name="set_type_variation">
+			<return type="void">
+			</return>
+			<argument index="0" name="theme_type" type="StringName">
+			</argument>
+			<argument index="1" name="base_type" type="StringName">
+			</argument>
+			<description>
+				Marks [code]theme_type[/code] as being a variation of [code]base_type[/code].
+				This adds [code]theme_type[/code] as a suggested option for [member Control.theme_type_variation] on a [Control] that is of the [code]base_type[/code] class.
+				Variations can also be nested, i.e. [code]base_type[/code] can be another variation. If a chain of variations ends with a [code]base_type[/code] matching a class of a [Control], the whole chain is going to be suggested as options.
+				Note: Suggestions only show up if this [Theme] is set as the project default theme. See [member ProjectSettings.gui/theme/custom].
+			</description>
+		</method>
 	</methods>
 	<members>
 		<member name="default_font" type="Font" setter="set_default_font" getter="get_default_font">
diff --git a/doc/classes/Window.xml b/doc/classes/Window.xml
index 73a95967bd..c8efaca1fc 100644
--- a/doc/classes/Window.xml
+++ b/doc/classes/Window.xml
@@ -347,7 +347,7 @@
 		</member>
 		<member name="theme" type="Theme" setter="set_theme" getter="get_theme">
 		</member>
-		<member name="theme_custom_type" type="StringName" setter="set_theme_custom_type" getter="get_theme_custom_type" default="&amp;&quot;&quot;">
+		<member name="theme_type_variation" type="StringName" setter="set_theme_type_variation" getter="get_theme_type_variation" default="&amp;&quot;&quot;">
 		</member>
 		<member name="title" type="String" setter="set_title" getter="get_title" default="&quot;&quot;">
 		</member>